This document relates to integrated circuits, and more particularly to assemblies having dies that include semiconductor integrated circuits.
In fabrication of integrated circuits, one or more circuits are manufactured in a semiconductor wafer and are then separated into “dies” (also called “chips”) in a process called “singulation” or “dicing”. The dies, such as shown at 110 in FIG. 1, are attached to a wiring substrate (“WS”, e.g. printed wiring board) 120 which has conductive lines 130 connecting the dies to each other and to other elements of the system. More particularly, the dies have contact pads 110C connected to the dies' circuits (not shown), and these contact pads are attached to contact pads 120C of WS 120. Pads 120C are interconnected by conductive lines 130. The attachment of pads 110C to pads 120C is performed by connections 140 which may include solder, conductive epoxy, or other types.
Encapsulant 150 (e.g. epoxy with silica or other particles) protects the dies 110 and the connections 140 from moisture and other contaminants, ultraviolet light, alpha particles, and possibly other harmful elements. The encapsulant also strengthens the die-to-WS attachment against mechanical stresses, and helps conduct heat away from the dies (to an optional heat sink 160 or directly to the ambient (e.g. air)).
It is desirable to provide improved protection of dies from mechanical stresses, heat, and harmful elements.